[Checkins] [zopefoundation/zope.interface] 28a0aa: Use 3.6.2 on Travis.

[Jason Madden]

  Branch: refs/heads/mac-use-362
  Home:   https://github.com/zopefoundation/zope.interface
  Commit: 28a0aa0befd04aeba98918de35d54ba6c78086e9
      https://github.com/zopefoundation/zope.interface/commit/28a0aa0befd04aeba98918de35d54ba6c78086e9
  Author: Jason Madden <jamadden at gmail.com>
  Date:   2020-01-21 (Tue, 21 Jan 2020)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Use 3.6.2 on Travis.

3.6.0 encounters https://github.com/nedbat/coveragepy/issues/703